1.2 Glossary

This document uses the following terms:

Active Directory: The Windows implementation of a general-purpose directory service, which uses LDAP as its primary access protocol. Active Directory stores information about a variety of objects in the network such as user accounts, computer accounts, groups, and all related credential information used by Kerberos [MS-KILE]. Active Directory is either deployed as Active Directory Domain Services (AD DS) or Active Directory Lightweight Directory Services (AD LDS), which are both described in [MS-ADOD]: Active Directory Protocols Overview.

administrator: A user who has complete and unrestricted access to the computer or domain.

attestation: A process of establishing some property of a computer platform or of a trusted platform module (TPM) key, in part through TPM cryptographic operations.

attribute: A characteristic of some object or entity, typically encoded as a name/value pair.

CA administrator: A human operator who is responsible for managing the CA system.

CA exit algorithm: An optional addition to the CA (WCCE server role) functionality. The algorithm is invoked whenever a certificate is issued. The algorithm can perform customer-defined, post-processing functionality such as publishing the certificate to a predefined path or sending an email message about the issued certificate to an administrator.

CA policy algorithm: An algorithm that determines whether to issue a certificate for a specified certificate request and defines how that certificate is constructed.

CA system: The system that implements the protocols and data structures specified in [MS-WCCE], [MS-CSRA], [MS-CRTD], and [MS-ICPR].

CEP: The certificate enrollment policy as defined in [MS-XCEP].

certificate: A certificate is a collection of attributes and extensions that can be stored persistently. The set of attributes in a certificate can vary depending on the intended usage of the certificate. A certificate securely binds a public key to the entity that holds the corresponding private key. A certificate is commonly used for authentication and secure exchange of information on open networks, such as the Internet, extranets, and intranets. Certificates are digitally signed by the issuing certification authority (CA) and can be issued for a user, a computer, or a service. The most widely accepted format for certificates is defined by the ITU-T X.509 version 3 international standards. For more information about attributes and extensions, see [RFC3280] and [X509] sections 7 and 8.

certificate enrollment: The process of acquiring a digital certificate from a certificate authority (CA), which typically requires an end entity to first makes itself known to the CA (either directly, or through a registration authority). This certificate and its associated private key establish a trusted identity for an entity that is using the public key–based services and applications. Also referred to as simply "enrollment".

certificate enrollment policy: The collection of certificate templates and certificate issuers available to the requestor for X.509 certificate enrollment.

certificate issuance: The granting of a digital certificate to an end entity by a certificate authority (CA) as part of the certification process. Sometimes referred to as simply "issuance".

certificate revocation list (CRL): A list of certificates that have been revoked by the certification authority (CA) that issued them (that have not yet expired of their own accord). The list must be cryptographically signed by the CA that issues it. Typically, the certificates are identified by serial number. In addition to the serial number for the revoked certificates, the CRL contains the revocation reason for each certificate and the time the certificate was revoked. As described in [RFC3280], two types of CRLs commonly exist in the industry. Base CRLs keep a complete list of revoked certificates, while delta CRLs maintain only those certificates that have been revoked since the last issuance of a base CRL. For more information, see [X509] section 7.3, [MSFT-CRL], and [RFC3280] section 5.

certificate template: A list of attributes that define a blueprint for creating an X.509 certificate. It is often referred to in non-Microsoft documentation as a "certificate profile". A certificate template is used to define the content and purpose of a digital certificate, including issuance requirements (certificate policies), implemented X.509 extensions such as application policies, key usage, or extended key usage as specified in [X509], and enrollment permissions. Enrollment permissions define the rules by which a certification authority (CA) will issue or deny certificate requests. In Windows environments, certificate templates are stored as objects in the Active Directory and used by Microsoft enterprise CAs.

certificate transparency: A feature that allows a digital certificate to be issued by a CA in response to a client request, while also enabling a compliant operator to monitor and audit a publicly available certificate transparency log to which the certificates are also sent.

certification authority (CA): A third party that issues public key certificates. Certificates serve to bind public keys to a user identity. Each user and certification authority (CA) can decide whether to trust another user or CA for a specific purpose, and whether this trust should be transitive. For more information, see [RFC3280].

Cryptographic Message Syntax (CMS): A public standard that defines how to digitally sign, digest, authenticate, or encrypt arbitrary message content, as specified in [RFC3852].

digital certificate: See the "digital certificate definition standard," as described in [X509].

Distributed Component Object Model (DCOM): The Microsoft Component Object Model (COM) specification that defines how components communicate over networks, as specified in [MS-DCOM].

domain controller (DC): The service, running on a server, that implements Active Directory, or the server hosting this service. The service hosts the data store for objects and interoperates with other DCs to ensure that a local change to an object replicates correctly across all DCs. When Active Directory is operating as Active Directory Domain Services (AD DS), the DC contains full NC replicas of the configuration naming context (config NC), schema naming context (schema NC), and one of the domain NCs in its forest. If the AD DS DC is a global catalog server (GC server), it contains partial NC replicas of the remaining domain NCs in its forest. For more information, see [MS-AUTHSOD] section and [MS-ADTS]. When Active Directory is operating as Active Directory Lightweight Directory Services (AD LDS), several AD LDS DCs can run on one server. When Active Directory is operating as AD DS, only one AD DS DC can run on one server. However, several AD LDS DCs can coexist with one AD DS DC on one server. The AD LDS DC contains full NC replicas of the config NC and the schema NC in its forest. The domain controller is the server side of Authentication Protocol Domain Support [MS-APDS].

encryption: In cryptography, the process of obscuring information to make it unreadable without special knowledge.

end entity: The keyholder (person or computer) to whose key or name a particular certificate refers.

enhanced key usage (EKU): An extension that is a collection of object identifiers (OIDs) that indicate the applications that use the key.

Enroll On Behalf Of (EOBO): A proxy enrollment process in which one user, typically an administrator, enrolls for a certificate for a second user by using the administrator credentials.

enterprise certificate authority (enterprise CA): A certificate authority (CA) that is a member of a domain and that uses the domain's Active Directory service to store policy, authentication, and other information related to the operation of the CA. Specifically, the enterprise CA is a server implementation of the Windows Client Certificate Enrollment Protocol that uses the certificate template data structure (see [MS-CRTD]) in its CA policy algorithm implementation.

entity: A unit that is part of the system such as a component or an element.

exchange certificate: A certificate that can be used for encryption purposes. This certificate can be used by clients to encrypt their private keys as part of their certificate request. In Windows environments, an enterprise certificate authority (CA) creates an exchange certificate periodically (by default, weekly), and returns the exchange certificate upon request of a client. For more information, see [MSFT-ARCHIVE].

Group Policy: A mechanism that allows the implementer to specify managed configurations for users and computers in an Active Directory service environment.

interface: A group of related function prototypes in a specific order, analogous to a C++ virtual interface. Multiple objects, of different object class, may implement the same interface. A derived interface may be created by adding methods after the end of an existing interface. In the Distributed Component Object Model (DCOM), all interfaces initially derive from IUnknown.

key: In cryptography, a generic term used to refer to cryptographic data that is used to initialize a cryptographic algorithm. Keys are also sometimes referred to as keying material.

key archival: The process by which the entity requesting the certificate also submits the private key during the process. The private key is encrypted such that only a key recovery agent can obtain it, preventing accidental disclosure, but preserving a copy in case the entity is unable or unwilling to decrypt data.

key attestation: See attestation.

key exchange: A synonym for key establishment. The procedure that results in shared secret keying material among different parties. Key agreement and key transport are two forms of key exchange. For more information, see [CRYPTO] section 1.11, [SP800-56A] section 3.1, and [IEEE1363] section 3.

key length: A value specified by a cryptographic module that indicates the length of the public-private key pair and symmetric keys that are used within the module. The key length values are expressed in bits. For more information about cryptographic key lengths, see [SP800-56A] section 3.1.

key recovery agent (KRA): A user, machine, or registration authority that has enrolled and obtained a key recovery certificate. A KRA is any entity that possesses a KRA private key and certificate. For more information on KRAs and the archival process, see [MSFT-ARCHIVE].

keyholder: The entity that holds a private key and is therefore capable of signing and decrypting. The keyholder of a public key is defined as the keyholder of the corresponding private key.

Lightweight Directory Access Protocol (LDAP): The primary access protocol for Active Directory. Lightweight Directory Access Protocol (LDAP) is an industry-standard protocol, established by the Internet Engineering Task Force (IETF), which allows users to query and update information in a directory service (DS), as described in [MS-ADTS]. The Lightweight Directory Access Protocol can be either version 2 [RFC1777] or version 3 [RFC3377].

PKI administrator: PKI administrators are responsible for implementing the company's policy by defining CEPs and setting up servers that provide certificates to clients.

policy server endpoint: A collection of information about a policy server, such as the protocol that it supports, its Uniform Resource Identifier (URI), and authentication to be used when accessing the server.

private key: One of a pair of keys used in public-key cryptography. The private key is kept secret and is used to decrypt data that has been encrypted with the corresponding public key. For an introduction to this concept, see [CRYPTO] section 1.8 and [IEEE1363] section 3.1.

public key: One of a pair of keys used in public-key cryptography. The public key is distributed freely and published as part of a digital certificate. For an introduction to this concept, see [CRYPTO] section 1.8 and [IEEE1363] section 3.1.

public key infrastructure (PKI): The laws, policies, standards, and software that regulate or manipulate certificates and public and private keys. In practice, it is a system of digital certificates, certificate authorities (CAs), and other registration authorities that verify and authenticate the validity of each party involved in an electronic transaction. For more information, see [X509] section 6.

public-private key pair: The association of a public key and its corresponding private key when used in cryptography. Also referred to simply as a "key pair". For an introduction to public-private key pairs, see [IEEE1363] section 3.

registration authority (RA): The authority in a PKI that verifies user requests for a digital certificate and indicates to the certificate authority (CA) that it is acceptable to issue a certificate.

remote procedure call (RPC): A communication protocol used primarily between client and server. The term has three definitions that are often used interchangeably: a runtime environment providing for communication facilities between computers (the RPC runtime); a set of request-and-response message exchanges between computers (the RPC exchange); and the single message from an RPC exchange (the RPC message).  For more information, see [C706].

revocation: The process of invalidating a certificate. For more details, see [RFC3280] section 3.3.

root CA: A type of certificate authority (CA) that is directly trusted by an end entity, including a relying party; that is, securely acquiring the value of a root CA public key requires some out-of-band steps. This term is not meant to imply that a root CA is necessarily at the top of any hierarchy, simply that the CA in question is trusted directly (as specified in [RFC2510]). A root CA is implemented in software and in Windows, is the topmost CA in a CA hierarchy, and is the trust point for all certificates that are issued by the CAs in the CA hierarchy. If a user, computer, or service trusts a root CA, it implicitly trusts all certificates that are issued by all other CAs in the CA hierarchy. For more information, see [RFC3280].

standalone CA: A certification authority (CA) that is not a member of a domain. For more information, see [MSFT-PKI].

trust: To accept another authority's statements for the purposes of authentication and authorization, especially in the case of a relationship between two domains. If domain A trusts domain B, domain A accepts domain B's authentication and authorization statements for principals represented by security principal objects in domain B; for example, the list of groups to which a particular user belongs. As a noun, a trust is the relationship between two domains described in the previous sentence.

trusted platform module (TPM): A component of a trusted computing platform. The TPM stores keys, passwords, and digital certificates. See [TCG-Architect] for more information.

WSTEP: WS-Trust Enrollment Extensions

XCEP: X.509 Certificate Enrollment Policy Protocol Specification